1. Field of the Invention
The present invention relates to inventory order selection or logistics systems and methods, and more particularly to systems for aiding order picking personnel in correctly and quickly filling orders, and more particularly still to automated paperless order selection systems of the type wherein an electronic order picking unit moves horizontally along a rail directly to a product storage location, thereby decreasing the distance traveled and time spent looking for the ordered product by the order picker and improving the accuracy of the order picking process.
2. Preliminary Discussion
A number of logistics systems for assisting order picking personnel in quickly and accurately filling orders in a warehouse environment are known in the prior art. Currently, such systems are used primarily in situations where workers must pick the correct number and type of individual units of a product ordered from a series of bins, and are designed to decrease both the number of selection errors committed and the time involved in each picking process or operation. However, in bulk inventory environments, wherein multiple units of a product are stored in cartons or cases, typically on a shelf or rack structure, rather than as individual units, it is still relatively common for order picking personnel to fill such orders using only a paper order form or listing of the ordered products, without the assistance of an automated order selection system. Upon receipt of an order for one or more cartons of a particular product, the worker will, usually relying on memory, locate the storage area for such product cartons, manually pick or remove from such storage area the number of cases or cartons indicated on the order list, move the cartons to a delivery station, and manually check, initial, or otherwise indicate on the order form whether or not the picking process has been successfully completed.
While paper order selection systems are somewhat reliable in relatively small or stable warehouse environments, in larger environments, where hundreds or even thousands of different items are stored, such paper based order systems are clearly inadequate. For example, as indicated above, order picking personnel using a paper system rely primarily on memory to quickly find each storage location, or at least to locate the general storage area for each type of product. However, the larger the warehouse or storage area, the more difficult it becomes for employees to remember all of such storage locations. In addition, employee turnover rates are likely to be higher in larger warehouse environments, so that even if certain longtime employees learn to quickly locate and pick items, newer employees are much less efficient and will waste significant time searching for such items. Thus, manual or paper picking in large warehouse environments is likely to be very inefficient.
It is also well known that order picking can be fairly tedious for the worker. As a result, even longtime or highly skilled personnel may make a larger than usual number of picking errors over his or her work shift, often accidentally picking the wrong type or quantity of a product. Such errors become even more prevalent where there are a number of separate but related products in a product line, such as, for example, where clothing items are sold in several different colors or styles. In addition, orders processed using paper systems are much more likely to be delayed, lost, or misplaced, than in automated systems, due to the human error factor.
In general, previous automated or paperless order picking systems have been either too expensive or too complicated to be implemented in a bulk inventory environment, or where implemented have been ineffective. Thus, there is still a need for an automated system to assist or aid order picking personnel in quickly locating the correct storage location for a given order. Such system should not only be paperless and should lead a worker directly to the correct storage location, but should also provide the order picker with information concerning the number and type of products to be picked, both visually and audibly, should aid the order picker in printing labels or readying such orders for delivery, and should allow the order picker to confirm to the order system when an order has been successfully filled.
3. Description of Related Art
As indicated above, warehouse logistics or order selection systems are generally are known in the prior art. For example, U.S. Pat. No. 4,792,273 issued to D. Specht on Dec. 20, 1988, entitled “Method and Apparatus for Documentless Order Picking of Goods”, discloses a documentless, computer-controlled order picking system to direct order pickers in selecting items from a series of bins, after which the items are placed into transport containers. Each time items are removed or picked from a bin, an acknowledgement switch indicates such picking to a central computer. In addition, illuminated arrows above each rack indicate generally the direction the order picker should move to pick the next item. Such indicator lights are stationary, however, and Specht does not disclose the use of an order picking unit or device movable along a rail system.
U.S. Pat. No. 5,781,443 issued to W. L. Street et al. on Jul. 14, 1998, entitled “Apparatus for Use in Parts Assembly”, discloses a computerized “kitting” system for directing order pickers in picking the correct number and type of inventory items. In Street et al., display screens are situated over each bin which display to the order picker the correct number of items to be removed from such bins. In addition, a sensing means is used to detect when an order picker places his or her hand in a bin. The Street et al. system is not capable of leading an order picker to a storage location as in the present invention, however.
None of the prior art patents of which the inventor is aware discloses a rack or rail type order selection system similar to the present system. In fact, the inventor is aware of only one other rack-type order selection system, which system is marketed by JEKA, Inc. under the trademark RackRunner®. In the JEKA system, a movable order picking unit is hung on a rail attached to a storage rack. Such order picking unit contains a bar code reader, and as the unit moves along the rail, it reads bar codes spaced along the rail, with each bar code label being indicative of individual storage or picking locations in the storage rack. The picking unit continues to move along the rail reading each bar code label until it locates a code corresponding to the code for the items to be selected, wherein presumably the items are stored in such location. The quantity of goods to be picked is displayed on a small display window on the picking unit, possibly along with other related information. The completion of the picking process can be signaled or confirmed to the system upon completion of picking at each location by pressing a button on the picking unit, which sends a confirmation signal to a central computer.
While the JEKA system operates in a manner that is broadly similar to the present inventor's system, it has several disadvantages not found in the present system. First, as indicated above, the JEKA system relies on a bar code scanner to read preprinted bar code labels adhered to the rail structure to identify each individual storage location. Thus, in the JEKA system the order picking units cannot move directly to individual storage locations, but instead must check each bar code along the rail, stopping only when the desired or correct code is encountered. Not only is it inconvenient and time consuming to adhere such bar code labels to the rail, which process is also subject to error, but it also requires that the picking units contain an internal scanner for reading each bar code. In addition, the physical positions of each picking unit on the support rail can only be imprecisely determined either visually or based on the position of the last bar code it has checked, making it difficult if not impossible to coordinate multiple picking units on a rail at the same time.
In contrast, in the present system, rather than relying upon bar codes to identify a picking location, each of the picking units contains an incremental encoder so that the precise position of the order picking units along the support rail can be easily identified at any time. The incremental encoder allows for far greater accuracy and precision in controlling and positioning and monitoring the picking units, so that more than one unit can be located on the same rail without fear of such units blocking or running into each other. The use of an incremental encoder rather than a bar code system also allows the units to move directly, and therefore more quickly, to the desired picking location, rather than having to check or read each bar code along the support rail. As a result, the present system does not search for a bar code which will indicate the correct storage location, but rather simply moves directly to such location.
The present system also has several other features not found in the JEKA system. For example, the user interface of the JEKA picking units contains only a small display window, which window is capable of displaying only a limited amount of information about each order to be picked. In contrast, the present inventor includes a touch sensitive display screen or system, which system allows information to be both more easily communicated to the order pickers, and to be input into the system by such order pickers. The present device also includes a pair of separate indicator switches, one for sending signals to the system computer indicating or confirming that an order has been filled, or, if for some reason the order was not successfully completely filled, a separate switch for relaying such information to the central computer. Another important feature of the present system not found in the JEKA system is an internal sound card connected to a speaker attached to the housing of the picking units, which is used to provide audible instructions to the order picking personnel concerning each order picking function. The combination of visible and audible instructions further decreases the possibility of picking errors occurring, as order picking personnel are further reminded of the number and type of products which are to be picked.